Some observers, however, questioned the necessity of deploying a weapon of that scale against a group whose estimated 600 to 800 fighters pose only a limited threat to the Afghan state. “There is no doubt that Isis are brutal and that they have committed atrocities against our people. But I don’t see why the bomb was dropped,” said the mayor of Achin, Naweed Shinwari. “It terrorised our people. My relatives thought the end of the world had come. Every day fighter jets, helicopters and drones are in the area.”

The US had sustained an air campaign to eradicate Isis in eastern Afghanistan for more than a year, and according to Borhan Osman, an Isis expert with the Afghanistan Analysts Network, it had already been effective. “Isis was on the brink of losing their stronghold. It didn’t seem like there was a need for such a dramatic military measure,” he said.